When a reducing tap is connected to a prior art 600 amp high voltage elbow, a spanner wrench is used to rotate the reducing tap onto a threaded stud inside the elbow. The reducing tap is coated in hardened epoxy that can crack or break when the wrench is attached to the reducing tap and force is applied. Typically, a torque wrench is coupled to a short spanner wrench. Due to the added distance from the center of the reducing tap to the square drive on the spanner wrench, additional stress is applied to the epoxy covering the reducing tap. In the past, one way to avoid damage to the epoxy coating was to reduce the tightening torque (see FIG. 1).
FIG. 1 shows a prior art 600 amp reducing elbow assembly that includes a 600 amp elbow A, a 600 amp bushing B and a 600 to 200 (600/200) amp reducing bushing C. The 600 amp bushing B has a threaded stud D connected to the end that connects to the elbow A. The 600 amp bushing B is inserted into one tap E of the elbow A and the 600/200 amp reducing bushing C is inserted into the opposing tap F of the elbow A. In order to secure the two bushings in the elbow A, the 600/200 amp reducing bushing C is rotated onto the threaded stud D using a spanner wrench G that fits around the outside of the 600/200 amp reducing bushing C. A torque wrench H can then be attached to the spanner wrench G to rotate the 600/200 amp reducing bushing C to the required torque.
The drawbacks to the elbow assembly shown in FIG. 1 include the overall dimensions of the assembly, the potential damage to the epoxy-coated reducing bushing that may be caused by the spanner wrench and the difficulty of applying the exact torque required to ensure a proper connection. Accordingly, there is a need for a 600 amp elbow with a 200/600 amp reducing tap that does not require the tap to be rotated when connected to the elbow.